Three terminal replaceable coulometric cells with known life periods mounted in an outer metallic can as one terminal are known in the art. Such cells at the end of life are destroyed in the manner of a fuse and need to be replaced. Thus, access to the conductive can terminal by a person is necessary, and thus if the cell is mounted in a high voltage circuit, it may present a shock hazard.
Removable connectors of the prior art suitable for use with such coulometric cells have been deficient in several respects. One of the weaknesses of such connectors are requirement for delicate parts, springs, sockets, etc. that are difficult to make and assemble and which lead to limited frictional engagement that may cause poor electrical connections. Also, the complexity and cost of connectors will prevent use of the cell in many applications which otherwise could use successfully a low priced electric timer device.
Wherever circuit conditions require a particular electrical device such as an electrolytic timing cell of unique characteristics it is also desirable to provide a connector which may be easily keyed to prevent insertion of the wrong device.
Complexity introduced by means of intermediate connector parts or soldered connections required by many prior art connectors tends to reduce reliability and increase places for failure to occur. The simplest possible connector device therefore has cost and performance advantages.